All participants were asked to return for A5260s clinic visits at weeks 4, 24, 48 96 and 144 and participated in all clinical evaluations. No clinical evaluation was restricted to a subset of A5260s participants. If a participant chose to discontinue participation in the substudy, the participant was able to continue in study A5257. However, a participant discontinuing participation from A5257 was also removed from A5260s. Additionally, a participant's decision to discontinue or switch study drugs in the main study did not impact participation and follow-up clinic visits in A5260s.